How would you market this? Tech focussed job board

From your post I'm assuming you're struggling to get traction with candidates, and not recruiters.

Marketing your product is great, but marketing isn't free, if you want traction you also need to figure out how to create a product which will spread through word of mouth.

Here are some generic tips:

• Speak to your users, find out what pain points they have
• Find niche communities, and start actively participating in them, organically promote your product when appropriate
• Implement a referral system so people can recommend others
• Automate recommendations based on what candidates applied to / looked at previously
• Remind people to come back an apply to jobs they've looked / started to apply to

Try things that don't scale:

• Reach out to people on linkedin who are looking for opportunities and send them a link to your site.
• Be more hands on with your existing candidates, work your ass for them to make sure they get the job
• Follow up with everyone who applied to a job personally and find out how it went
• Follow up with recruiters personally to ensure your candidates get feedback / answers

I'd love to chat about your business and understand your challenges better, so that I can give you some more specific suggestions. Hit me up on LinkedIn if you'd like to chat - https://www.linkedin.com/in/thatseika/

Do you have a problem on the supply (candidates) or demand (employers) side?

Different remedy for each I think.

I have worked on Job board with keeping USA as a target market. Here is my take on it!

This is a highly competitive space. I would suggest that you should start building a community around your cohort or partner with one.

Start with asking a question, where are my users?

Typical answers for your business:
Niche tech communities
YouTube Channels such as TechLead, Dev Ed, etc
Medium (?)
StackOverflow
Reddit/Quora(?)
Websites offering tech courses

Now here is a difficult part: Experimentation
Not all the channels that I listed above will work. You have to hustle your way through it to figure which one is working and which one is not worth the effort. You can either partner with them or run low CPM ads on these platforms. Based on your revenue model, you will have profitable channels. Then double down on it.

Also curious to know, if you source your own job listings by approaching companies/startups or you have API integration. If former, then it makes sense for you to have public APIs and get yourself listed on API marketplaces and get the growth engine going. I believe you can use the same for posting jobs on Linkedin too. I think paid Linkedin integration exists which you can explore.

Hey Chris, did you try to collaborate with Twitter influencers? Maybe it makes sense to collaborate with those who spread information for example about React to promote React job listings from your service

I would suggest using LinkedIn, people there are more into looking for jobs and connecting with professionals. You can create a Company page and make posts about the jobs you're offering.

Also, you can search for people looking for jobs in London and recommend your site to them.